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I’m with you on that. It seems like replacement at 150k miles is a little premature if we reverse the calc (that would 500 cycles) . I’m wondering what others are seeing, maybe it’s just a one-off lemon of a battery - otherwise I’d be a little squirrelly about what’s in store in a few years…A daily charge is not a cycle.
Sure, it may be premature. But batteries aren't exact science. A 300k mile average tends to mean that for everyone that fails at 150K, there's another that makes it to 450k.I’m with you on that. It seems like replacement at 150k miles is a little premature if we reverse the calc (that would 500 cycles) . I’m wondering what others are seeing, maybe it’s just a one-off lemon of a battery - otherwise I’d be a little squirrelly about what’s in store in a few years…
For cycles vs lifetime we should use Full Equivalent Cycles (FCE) as the term to relate to.Has anyone come across stats on the usual mileage for battery replacement on model 3s? A recent post got me wondering if that 1500 cycle figure is right (this person needs a replacement at 150k).
Thanks for the detailed response. It sounds like you’re saying that 1500 cycles we hear refers to partial cycles and those cells really only withstand 750 FCE ? Or do you mean that discharging from a lower SOC is less hard on a pack even when the total kWh used is the same (2x 50-0 vs 1x 100-0) ?For cycles vs lifetime we should use Full Equivalent Cycles (FCE) as the term to relate to.
One 100-0% charge-discharge cycle is one FCE. We need three 0-33% charge-discharge cycles for 1 FCE.
Or ten charge-discharge cycles of 10% DoD, for example 60-70%.
FCE will directly relate to how much energy the battery deliver (or miles that can be driven) compated to the degradation.
A Panasonic NCA, like Tesla model S/X or model 3 and Y in US would stand about 750FCE if we charge to 100% and discharge to 0% each time.
This would equal about 260K km (160K km).
But we do not use it like that, mostly.
Smaller discharge cycles reduce the degradation. All these are still discharged to 0%, but the charge level is varied.
4.2V = 100%
3.7V = about 50%
(About 10% per 10%)
View attachment 972268
(source: Research report )
We can see that the battery only lost 10% during the first 1000 cycles from the 3.7V / 50% - 0%. The inclination and bent form of the line show us that we would get perhaps 2500-3000 FCE in that case.
Most cars are cycled with relatively small cycles that wear even less.
But: Cyclic aging is only a small part of the degradation, calendar aging takes a bigger bite of the battery in the early battety life.
When batteries start getting old and work bad, it is the total degradation that matters so cyclic + calendar aging.
This persion needing a replacement after 150K, is it because the cells is worn out or is it another fault in the battery?
Its much more common to have other issues than that the cells is worn out.
1500cycles was from your friend.Thanks for the detailed response. It sounds like you’re saying that 1500 cycles we hear refers to partial cycles and those cells really only withstand 750 FCE ?
Yes, thats the basic thingOr do you mean that discharging from a lower SOC is less hard on a pack even when the total kWh used is the same (2x 50-0 vs 1x 100-0) ?
This is a picture of a cycle test of actual model 3 LR cells taken out of a not to old model 3:The post I saw only mentions the model awd is 3 yrs old and has 150k miles (so beyond the warranty). It got me wondering what others are seeing mileage-wise before replacement is needed.
The battery consists of cells, BMS-computer and contactors (relays).Seems like they might have a faulty battery given the mileage and age of the car yet somehow it’s considered out of warranty.
Original post Here
makes me wonder about this roadtrip super charging strategy of low SOC arrivals (5-10 %) . If those lower SOC arrivals are harsh on the battery, it doesn’t seem worth the faster travel.…You don't want to bring the battery down to zero, or a very low state, as this has a big impact on cycle life. ..
It’s a myth. Low SOC is fine for the battery. You just don’t want to run it completely dead (to where it shuts off) and then leave it there.makes me wonder about this roadtrip super charging strategy of low SOC arrivals (5-10 %) . If those lower SOC arrivals are harsh on the battery, it doesn’t seem worth the faster travel.
Just as @E90alex says.makes me wonder about this roadtrip super charging strategy of low SOC arrivals (5-10 %) . If those lower SOC arrivals are harsh on the battery, it doesn’t seem worth the faster travel.